Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to random access channel (RACH).
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.
A user equipment (UE) camps on a cell using a cell selection or cell reselection procedure. However, the UE may camp on the cell without being in close physical proximity. In such cases, the UE can receive DL signaling messages, for example, system information block (SIB) messages from the cell, but the uplink transmitted messages, for example messages transmitted on the random access channel (RACH) may not reach the cell the UE is camped. The UE may try to communicate with the cell until the cell reselection criteria is satisfied.
In the above scenario, if the UE tries to transmit the radio resource control (RRC) connection request, timer T300 will expire without any success resulting in a degraded user experience. However, for a UE in such areas, the effect of the issue may be temporary because the UE can move out to other areas served by other cells. But for a user with low mobility, for example, vending machines, smart meters, etc., the effect on the performance is high as the low mobility user may have less opportunity to select another cell.
Therefore, there is a desire for a method and apparatus for improving uplink performance at a user equipment.